Why does desertification create problems for the environment

These unsustainable land uses place enormous pressure on the land by altering its soil chemistry and hydrology. Eventually, overexploited drylands suffer from erosion, soil salinization, loss of productivity, and decreased resilience to climatic variations. Land management plays a particularly large role in highly populated regions of less developed countries, where population growth is placing increased pressures on marginal lands.

Global warming due to the atmospheric buildup of carbon dioxide and other gases emitted by fossil fuel combustion threatens to complicate this picture in the future. A rise in global temperatures is likely to accelerate the process of desertification as evaporation rates increase.

A similar effort is underway in northern China , with the government planting trees along the border of the Gobi desert to prevent it from expanding as farming, livestock grazing , and urbanization , along with climate change, removed buffering vegetation. However, the results for these types of restoration efforts so far have been mixed. One type of mesquite tree planted in East Africa to buffer against desertification has proved to be invasive and problematic.

The Great Green Wall initiative in Africa has evolved away from the idea of simply planting trees and toward the idea of " re-greening ," or supporting small farmers in managing land to maximize water harvesting via stone barriers that decrease water runoff, for example and nurture natural regrowth of trees and vegetation. All rights reserved. Where is desertification happening, and why?

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But will they invade your privacy? Go Further. The Sahel is a narrow belt of land which lies immediately to the south of the Sahara Desert and which extends across most of Africa. The main causes of desertification include:. Causes of desertification Desertification is the process of land turning into desert as the quality of the soil declines over time.

The main causes of desertification include: Population growth - the population in some desert areas is increasing. In places where there are developments in mining and tourism, people are attracted by jobs. Soil erosion in Kenya. And typically, respiration declines with decreasing soil moisture to a point where microbial activity effectively stops. While this reduces the CO2 the microbes release, it also inhibits plant growth, which means the vegetation is taking up less CO2 from the atmosphere through photosynthesis.

Overall, dry soils are more likely to be net emitters of CO2. So as soils become more arid, they will tend to be less able to sequester carbon from the atmosphere, and thus will contribute to climate change. Other forms of degradation also generally release CO2 into the atmosphere, such as deforestation , overgrazing — by stripping the land of vegetation — and wildfires.

But coming up with a robust global estimate for desertification is not straightforward, explains Kimutai:. The multiplicity and complexity of the processes of desertification make its quantification even more difficult. Studies have used different methods based on different definitions.

And identifying desertification is made harder because it tends to emerge relatively slowly, adds Michaelides:. By the time it is detected, it may be hard to halt or reverse. Status of desertification in arid regions of the world. Taken from Dregne, H.

The GLASOD project was itself based on expert judgement, with more than soil and environmental scientists contributing to regional assessments that fed into its global map, which it published in It categorised the degradation into chemical red shading , wind yellow , physical purple or water blue. Shading indicates type of degradation: chemical red , wind yellow , physical purple and water blue , with darker shading showing higher levels of degradation.

Source: Oldeman, L. As the report puts it:. A single global map of land degradation cannot satisfy all views or needs.

The parts of the world with the most potential issues shown by orange and red shading — such as India, Pakistan, Zimbabwe and Mexico — are thus identified as particularly at risk from degradation. Shading indicates the number of coincident risks. The areas with the fewest are shown in blue, which then increase through green, yellow, orange and the most in red. Credit: Publication Office of the European Union. As desertification cannot be characterised by a single metric, it is also tricky to make projections for how rates of degradation could change in the future.

In addition, there are numerous socio-economic drivers that will contribute. For example, the number of people directly affected by desertification is likely to increase purely because of population growth. The impact of climate change on aridity is also complicated. A warmer climate is generally more able to evaporate moisture from the land surface — potentially increasing dryness in combination with hotter temperatures. These policies include a shift to low-carbon energy technologies and the deployment of carbon capture and storage.

In RCP4. By , global temperatures are likely to rise by C above pre-industrial levels. However, climate change will also affect rainfall patterns, and a warmer atmosphere can hold more water vapour, potentially increasing both average and heavy rainfall in some areas. There is also a conceptual question of distinguishing long-term changes in the dryness of an area with the relatively short-term nature of droughts. In general, the global area of drylands is expected to expand as the climate warms.